1. Field of the Invention
The present invention relates to a charge compensator for a voltage regulator in a semiconductor device, and more particularly, to an improved charge compensator for adjusting charge compensation in accordance with characteristics of a semiconductor device.
2. Description of the Related Art
Semiconductor devices need a voltage regulator which is able to generate electric potential of an analog level and to provide appropriate charge required for supplying the generated potential. A voltage regulator generally includes a comparator which detects a difference between an output voltage to a load and a reference voltage, and feeds back the difference to an input of the comparator to maintain the output voltage at the reference voltage level. A gain of the comparator and a feedback speed of the voltage regulator depend on amount of charge drawn per unit time through the output of the voltage regulator. As more charge is drawn through the output of the voltage regulator per unit time, more current is needed to satisfy a required performance demand. As a result, the voltage regulator needs a larger area due to the need for more current, and it causes the size of semiconductors to increase.
In addition to developments in designing efficient voltage regulators, various circuits have been devised to reduce consumption of the charge drawn through the voltage regulator output. One of these circuits is a charge compensator. A charge compensator detects a transition region where a load connected to the voltage regulator output is changed from a steady state to another steady state. At the transition region, the charge compensator provides the load with an appropriate amount of charge from a steady power source, for example, a power supply voltage Vdd.
However, since conventional charge compensators are designed only in consideration of variations in state of the load connected to the voltage regulator output, there is a problem that the charge drawn through the voltage regulator output cannot be properly compensated for variations in operating conditions of a semiconductor device. For example, an amount of the charge drawn by the load connected to the voltage regulator changes depending on manufacturing processes, voltages in use and temperatures of the semiconductor. Nonetheless, the conventional charge compensators are designed regardless of such operating conditions, so that the charge compensators cannot provide an appropriate amount of charge sufficient for compensating for the variations in the operating conditions of a semiconductor.
Therefore, a need exists for a charge compensator for efficiently compensating the charge drawn by the load for variations in the operating conditions and characteristics of a semiconductor.